Issue 15, 2024

Star-PCL shape memory polymer (SMP) scaffolds with tunable transition temperatures for enhanced utility

Abstract

Thermoresponsive shape memory polymers (SMPs) prepared from UV-curable poly(ε-caprolactone) (PCL) macromers have the potential to create self-fitting bone scaffolds, self-expanding vaginal stents, and other shape-shifting devices. To ensure tissue safety during deployment, the shape actuation temperature (i.e., the melt transition temperature or Tm of PCL) must be reduced from ∼55 °C that is observed for scaffolds prepared from linear-PCL-DA (Mn ∼ 10 kg mol−1). Moreover, increasing the rate of biodegradation would be advantageous, facilitating bone tissue healing and potentially eliminating the need for stent retrieval. Herein, a series of six UV-curable PCL macromers were prepared with linear or 4-arm star architectures and with Mns of 10, 7.5, and 5 kg mol−1, and subsequently fabricated into six porous scaffold compositions (10kl, 7.5kl, 5kl, 10k★, 7.5k★, and 5k★) via solvent casting particulate leaching (SCPL). Scaffolds produced from star-PCL-tetraacrylate (star-PCL-TA) macromers produced pronounced reductions in Tm with decreased Mnversus those formed with the corresponding linear-PCL-diacrylate (linear-PCL-DA) macromers. Scaffolds were produced with the desired reduced Tm profiles: 37 °C < Tm < 55 °C (self-fitting bone scaffold), and Tm ≤ 37 °C (self-expanding stent). As macromer Mn decreased, crosslink density increased while % crystallinity decreased, particularly for scaffolds prepared from star-PCL-TA macromers. While shape memory behavior was retained and radial expansion pressure increased, this imparted a reduction in modulus but with an increase in the rate of degradation.

Graphical abstract: Star-PCL shape memory polymer (SMP) scaffolds with tunable transition temperatures for enhanced utility

Supplementary files

Article information

Article type
Paper
Submitted
08 Janv. 2024
Accepted
13 Marts 2024
First published
26 Marts 2024
This article is Open Access
Creative Commons BY-NC license

J. Mater. Chem. B, 2024,12, 3694-3702

Star-PCL shape memory polymer (SMP) scaffolds with tunable transition temperatures for enhanced utility

C. T. Roberts, S. K. Beck, C. M. Prejean, L. M. Graul, D. J. Maitland and M. A. Grunlan, J. Mater. Chem. B, 2024, 12, 3694 DOI: 10.1039/D4TB00050A

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